Diverter valves have been known for some time for a variety of purposes. They are well known for use with bidets, tub-shower combinations and whirlpools. In bidets, the water flow may be diverted from the rim of the bidet to a spray outlet located towards the front of the bidet. In tub-shower combinations, diversion is from the tub spout to the shower, with the normal flow being to the tub spout. The use of back-flow preventers or vacuum breakers in such diverter valves is known in order to prevent contamination of the potable water supply. This becomes particularly important in the case of tub spout-hand shower assemblies where the hand shower may be placed in contaminated water during use.
There has already been described in U.S. Pat. No. 4,589,438 issued May 20, 1986 to Silvano Breda a diverter valve for use in a tub transfer assembly which valve comprises a main body chamber with inlet and outlet openings, a centrally disposed vertical inlet tube having a floating vacuum breaker assembly at its remote end, movable in response to changes in flow direction and pressure; the main chamber having another cylinder mounted therein with lateral openings, which openings may selectively engage the lateral outlet openings of the central chamber to permit flow thereto from an inlet opening.
U.S. Pat. No. 3,180,352 discloses an anti-siphon, non-spill valve. Water does not spill out a air vent because a combine check and float valve is used in the structure. Upper and lower valve seats are provided for the valve to ensure closure of the air vent.
A double seat valve cone is employed in a diverter assembly disclosed in U.S. Pat. No. 4,224,962 wherein flow is transferred from a tub to a shower. The valve is spring biased for flow to the tub and is designed for extremely low operating pressures. Connected parts move independently of each other through an extended valve stroke which would seem to contribute to the low pressure sensitivity of the system.
U.S. Pat. No. 4,326,671 discloses an anti-siphon valve and diverter for use in a water sprinkling system.
U.S. Pat. No. 3,144,873 discloses a dishwashing device which incorporates a diverter valve for transferring fluid flow between a spray and a spout (first and second outflow passages). The device includes a total of three back-flow prevention means or valves. The first is a flexible valve ring which is automatically sucked against a plurality of inlet bores when pressure in the inlet falls below atmospheric pressure. This places a diverter chamber, through a bypass bore and first outflow passage, in communication with atmosphere via a spout. The second check valve comprises a flared skirt or valve which expands and contracts against a wall in response to reverse flow in the device. The third check valve is located in a tube which is remote from the main assembly.
Thus, although the prior art does disclose assemblies which incorporate both diverter and back-flow or vacuum breaker means, there does not appear to be available commercially a well designed tub transfer diverter valve assembly which is reliable, easily manufactured, installed and serviced, and which also permits flexibility of installation with respect to location and variety of aesthetic finishes. In practice, such assemblies should have good flow rates without leakage through any of the back-flow or vacuum breaker means. The assembly should also include a back-flow preventer means which will permit the clearing out of standing water from the assembly when the tub spout is positioned at a point higher than the point at which the transfer valve is located. The provision of a structure combining all these functions in one unit would clearly be highly desirable from the commercial point of view, since it would help reduce inventory requirements.